JP2018040927A - Stereoscopic endoscope imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stereoscopic endoscope imaging device that has an optical system less in stray light.SOLUTION: A stereoscopic endoscope imaging device has: a first optical system that is arranged on a first optical path, and creates a first optical image; a second optical system that is arranged on a second optical path, and creates a second optical image; and an image pick-up elements shoots the first optical image and the second optical image. On each of the first optical path and the second optical path, a parallel flat plate and an optical path conversion element are located, and the parallel flat plate and the optical path conversion element are integrated. The parallel flat plate is composed of a single member, in which a prescribed position is an arbitrary position between an object side face of the parallel flat plate and an image side face of the optical path conversion element. In the first optical system and the second optical system, at the prescribed position, a light ray height of an on-axis light flux and a light ray height of an off-axis light flux are lowest, and a first opening part and a second opening part are together located closer to an object side than the prescribed position, or are located closer to an image side than the prescribed position.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an imaging apparatus for a stereoscopic endoscope.

  A perspective endoscope is disclosed in Patent Documents 1 to 3. The perspective endoscope of Patent Document 1 includes a front group, a visual field direction conversion element, a rear group, and an imaging element. The visual field direction changing element is disposed between the front group and the rear group.

  The perspective endoscope of Patent Document 2 is an endoscope capable of stereoscopic viewing. In the perspective endoscope of Patent Document 2, an objective optical system, a relay optical system, and a primary imaging optical system are arranged on a common optical path. The objective optical system has a perspective prism optical system.

  Two optical paths are formed on the image side of the common optical path. In each optical path, an opening, a secondary imaging optical system, and an image sensor are arranged. The two openings are formed in one plate-like member.

  The perspective endoscope of Patent Document 3 is an endoscope capable of stereoscopic viewing. In the endoscope for perspective of Patent Document 3, only two optical paths are formed. A front group, a reflecting member, and a rear group are arranged in each optical path. The reflecting member of one optical path and the reflecting member of the other optical path are configured by one member.

  Usually, light enters the optical system from various directions. Part of the incident light is reflected inside the lens frame. The reflected light travels in various directions depending on the reflection direction and the number of reflections. Among these, a part of the reflected light is directed to the image position.

  The reflected light (hereinafter referred to as “stray light”) toward the image position may be diverged at the image position or may be converged. The stray light is also called flare, ghost, or the like, and is unnecessary for the original image of the object. Therefore, when stray light overlaps with the optical image, the contrast and resolution of the optical image are lowered.

  When there is only one optical path in the optical system, one optical image is formed. In an optical system having only one optical path, the contrast and resolution of the optical image are not degraded unless stray light overlaps the optical image.

  When the optical path of the optical system is two, two optical images are formed. In an optical system having two optical paths, if the stray light generated in one optical path does not overlap with one optical image, the contrast and resolution of the one optical image are not lowered.

  However, in an optical system with two optical paths, the other optical path is located next to one optical path. Therefore, in some cases, stray light generated in one optical path enters the other optical path. At this time, even if stray light is incident on the other optical path, the contrast and resolution of the other optical image are not lowered unless the stray light overlaps the other optical image. However, if the stray light overlaps with the other optical image, the contrast and resolution of the other optical image are lowered.

  Further, when stray light is generated in an imaging apparatus for stereoscopic observation, the image of the stray light often differs between the left eye image and the right eye image. In particular, during stereoscopic observation, if different images are displayed for the left-eye image and the right-eye image, a problem that leads to great fatigue occurs.

Japanese Patent No. 5558058 JP 7-236610 A JP 2006-317891 A

  In the perspective endoscope of Patent Document 1, the optical system is configured by only one optical path. Therefore, no consideration is given to stray light generated in an optical system including only two optical paths.

  In the perspective endoscope disclosed in Patent Document 2, the optical system includes a common optical path and two optical paths. Therefore, no consideration is given to stray light generated in an optical system having no common optical path, that is, stray light generated in an optical system including only two optical paths.

  In the perspective endoscope of Patent Document 3, the optical system is configured by only two optical paths. However, no consideration is given to stray light.

  The present invention has been made in view of such a problem, and is a stereoscopic endoscope in which an optical system is configured by only two optical paths, and an imaging apparatus for a stereoscopic endoscope having an optical system with little stray light The purpose is to provide. Another object of the present invention is to provide a stereoscopic endoscope imaging device that is easy to manufacture.

In order to solve the above-described problems and achieve the object, a stereoscopic endoscope imaging apparatus according to at least some embodiments of the present invention includes:
A first optical system disposed in the first optical path and generating a first optical image;
A second optical system disposed in the second optical path and generating a second optical image;
An image sensor that captures the first optical image and the second optical image,
A parallel plate and an optical path conversion element are located in each of the first optical path and the second optical path,
The parallel plate and the optical path conversion element are integrated.
The parallel plate is composed of a single member,
The predetermined position is an arbitrary position between the object side surface of the parallel plate and the image side surface of the optical path conversion element,
In the first optical system and the second optical system, the light beam height of the on-axis light beam and the light beam height of the off-axis light beam are the lowest at a predetermined position.
The first opening is located in the first optical path,
The second opening is located in the second optical path,
Both the first opening and the second opening are located on the object side of the predetermined position, or are located on the image side of the predetermined position.

  According to the present invention, it is possible to provide a stereoscopic endoscope imaging apparatus having an optical system with little stray light in a stereoscopic endoscope in which an optical system is configured by only two optical paths. In addition, an imaging apparatus for a stereoscopic endoscope that can be easily manufactured can be provided.

It is a figure which shows the structure and stray light of the imaging device for stereoscopic endoscopes of this embodiment. It is a figure which shows the example of arrangement | positioning of an opening part. It is a figure which shows another example of arrangement | positioning of an opening part. It is a figure which shows the specific example 1 of an opening part. It is a figure which shows the specific example 2 of an opening part. It is a figure which shows the specific example 3 of an opening part. It is a figure which shows the specific example 4 of an opening part. It is a figure which shows the specific example 5 of an opening part. It is a figure which shows the example of arrangement | positioning of an aperture stop. It is a figure which shows an optical path conversion element. It is sectional drawing of the optical system for stereoscopic endoscopes.

  Hereinafter, embodiments and examples of a stereoscopic endoscope imaging apparatus according to the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment and an Example.

  The stereoscopic endoscope imaging apparatus of the present embodiment is disposed in a first optical path, and is disposed in a first optical system that generates a first optical image, a second optical path, and the second optical image. A second optical system to be generated; an image sensor that captures the first optical image and the second optical image; a parallel plate on each of the first optical path and the second optical path; and optical path conversion The parallel plate and the optical path conversion element are integrated. The parallel flat plate is formed of a single member, and the predetermined position is an image of the object side surface of the parallel plate and the optical path conversion element. In the first optical system and the second optical system, the light beam height of the on-axis light beam and the light beam height of the off-axis light beam are the lowest at a predetermined position. The opening is located in the first optical path, the second opening is located in the second optical path, and the first opening and the second opening are both objects than the predetermined position. Located in or, characterized in that positioned on the image side of the predetermined position.

  FIG. 1 is a diagram illustrating the configuration and stray light of the stereoscopic endoscope imaging apparatus of the present embodiment. In the stereoscopic endoscope imaging apparatus of the present embodiment, the optical system has a first optical path OP1 and a second optical path OP2. However, the optical system does not have a common optical path.

  The first optical system OBJ1 is disposed in the first optical path OP1. A first optical image I1 is formed by the first optical system OBJ1. A second optical system OBJ2 is disposed in the second optical path OP2. A second optical image I2 is formed by the second optical system OBJ2.

  The first optical image I1 and the second optical image I2 are captured by the image sensor IS. In FIG. 1, there is one image sensor IS, but two image sensors may be used. When two image sensors are used, the first optical image I1 is imaged by one image sensor, and the second optical image I2 is imaged by the other image sensor.

  The same optical system is used for the first optical system OBJ1 and the second optical system OBJ2. The optical system includes, in order from the object side, a negative lens L1, a positive lens L2, a negative lens L3, a parallel plate PL, an optical path conversion element PR, a positive lens L4, a negative lens L5, and a positive lens L6. Have.

  The positive lens L2 and the negative lens L3 are cemented. The negative lens L5 and the positive lens L6 are cemented. A cover glass C1 and a cover glass C2 are arranged on the image side of the positive lens L6. The cover glass C1 and the cover glass C2 are joined. The cover glass C2 is a cover glass of the image sensor IS.

  The parallel plate PL and the optical path conversion element PR are integrated. The parallel plate PL is composed of a single member. Accordingly, the parallel plate PL has such a size as to be located in both the first optical path and the second optical path.

  The optical path conversion element PR may be composed of a single member or may be composed of two members. In the optical path conversion element PR, the first optical path and the second optical path are each bent.

  For example, a right-angle prism can be used as the optical path conversion element PR. In this case, the optical path located on the image side of the optical path conversion element PR is formed in a direction orthogonal to the paper surface. For ease of viewing, FIG. 1 shows a state where the optical path is not bent.

  The stray light will be described. FIG. 1 shows the state of stray light. Here, the state of stray light is qualitatively shown. That is, the refraction of light in the lens is not considered. Therefore, the stray light is drawn in a straight line.

  In FIG. 1, stray light is reflected twice by the inner surface of the lens frame BAL. However, in actuality, since refraction by the lens occurs, the second reflection may not occur.

The stray light LB _flar incident on the first optical path OP1 reaches a point P _in1 on the inner surface of the lens frame BAL. The stray light LB _flar is reflected at the point P _in1 and reaches the point P _in2 on the inner surface of the lens frame BAL. The stray light LB _flar is reflected at the point P _in2 and overlaps with the second optical image I2.

When stray light LB _flar is condensed at the image position, a ghost overlaps the second optical image I2. Further, when the stray light LB _flar is diffused at the image position, the flare overlaps with the second optical image I2. In either case, in the second optical image I2, a decrease in contrast and a decrease in resolution occur.

A first optical system OBJ1 in the second optical system OBJ2, at a predetermined position, the height of light rays ray height and the off-axis light flux LB _Offax the axial beam LB _ax is the lowest. The first optical system OBJ1 and the second optical system OBJ2 are so designed. The predetermined position is an arbitrary position between the object side surface of the parallel plate PL and the image side surface of the optical path conversion element PR.

  When a predetermined position exists between the object side surface of the parallel plate PL and the image side surface of the optical path conversion element PR, the light beam height on the parallel plate PL and the light beam height on the optical path conversion element PR are lowered. Therefore, the parallel plate PL and the optical path conversion element PR can be reduced in size.

As shown in FIG. 1, in the range from the image side surface of the negative lens L3 to the object side surface of the parallel plate PL (hereinafter referred to as “range A”), the stray light LB _flar is transmitted on the axial light beam LB _ax or off-axis light beam LB _offax. Away from. Therefore, by providing the opening in the range A, the stray light LB _flar can be shielded.

Similarly, the stray light LB _flar is separated from the on-axis light beam LB _ax and the off-axis light beam LB _{offax in} a range closer to the image side than the image side surface of the optical path conversion element PR (hereinafter referred to as “range B”). Therefore, by providing the opening in the range B, the stray light LB _flar can be shielded.

The stray light LB _flar is generated in both the first optical path OP1 and the second optical path OP2. Therefore, it is preferable to provide the opening in both the first optical path OP1 and the second optical path OP2. That is, the first opening is positioned in the first optical path OP1, and the second opening is positioned in the second optical path OP2.

  The range A is located closer to the object side than the predetermined position. The range B is located on the image side with respect to the predetermined position. Therefore, the first opening and the second opening may be positioned closer to the object side than the predetermined position, or may be positioned closer to the image side than the predetermined position.

  In FIG. 1, dotted lines are drawn in the vicinity of the object side surface of the parallel plate PL and in the vicinity of the image side surface of the optical path conversion element PR. This dotted line is located closer to the object side than the predetermined position, or closer to the image side than the predetermined position. Therefore, the first opening and the second opening may be positioned at the position indicated by the dotted line. By doing so, stray light can be shielded.

  As a result, an imaging apparatus for a stereoscopic endoscope having an optical system with little stray light can be realized. Further, since stray light can be reduced, ghosts and flares superimposed on the optical image can be reduced. Therefore, it is possible to prevent a decrease in contrast and resolution in the optical image.

  Further, as described above, the parallel plate PL and the optical path conversion element PR are integrated. An example of the integration method is joining. In joining, for example, an adhesive is used.

  As described above, the optical path conversion element PR may be composed of a single member or may be composed of two members. When the optical path conversion element PR is composed of a single member, the optical path conversion element PR may be joined to the parallel plate PL.

  When the optical path conversion element PR is composed of two members, the two members may be joined separately to the parallel plate PL. Alternatively, after joining the two members, the joined two members may be joined to the parallel plate PL.

  As shown in FIG. 1, the parallel plate PL and the optical path conversion element PR are incorporated in the lens frame BAL. When the parallel plate PL and the optical path conversion element PR are separately incorporated during incorporation into the lens frame BAL, adjustment becomes difficult.

  Since the parallel plate PL is composed of a single member, the shape and size of the outer diameter can be freely set. Therefore, the outer diameter of the parallel plate PL can be made larger than that of the optical path conversion element PR.

  At this time, the outer diameter of the parallel plate PL is made into a shape suitable for positioning and processed with high accuracy. Then, the parallel plate PL and the optical path conversion element PR are integrated. By doing in this way, positioning with respect to the lens frame BAL can be performed only by the parallel plate PL. For this reason, adjustment when incorporated in the lens frame BAL is facilitated.

  Further, in the method in which the parallel plate PL and the optical path conversion element PR are integrated in advance, since the lens frame BAL does not exist, the position and inclination of the parallel plate PL and the optical path conversion element PR can be easily measured. Therefore, adjustment before joining becomes easy. As a result, errors during assembly can be reduced.

  In the optical system of the endoscope, the size of the parallel plate PL and the size of the optical path conversion element PR are very small. Therefore, if the parallel plate PL and the optical path conversion element PR are integrated, the size as one component is increased, so that the handling becomes easy. As a result, work efficiency during assembly can be improved.

  Thus, in the stereoscopic endoscope imaging apparatus of the present embodiment, errors during assembly can be reduced, and work efficiency during assembly can be improved. Therefore, it is possible to provide a stereoscopic endoscope imaging device that is easy to manufacture.

  As another method of integration, for example, there is holding by a metal frame or a resin frame. Even if it does in this way, the effect similar to integration by joining can be acquired.

  In the stereoscopic endoscope imaging apparatus of the present embodiment, it is preferable that the first opening and the second opening are located on the object side with respect to a predetermined position.

  Since light rays are incident from various directions from the object side, many light rays are reflected on the inner surface of the lens frame BAL located on the object side from the predetermined position. Therefore, by arranging the opening on the object side from the predetermined position, it is possible to take a configuration in which reflected light (stray light) does not pass through a desired position efficiently or a configuration in which reflected light is not generated. Therefore, it is possible to realize a stereoscopic endoscope imaging apparatus having an optical system with little stray light. In addition, an imaging apparatus for a stereoscopic endoscope that can be easily manufactured can be realized.

  In the stereoscopic endoscope imaging apparatus of the present embodiment, it is preferable that the first opening and the second opening are located on the object side surface of a parallel plate.

FIG. 2 is a diagram illustrating an arrangement example of openings. As shown in FIG. 2, the position P1 is the position of the joint surface between the parallel plate PL and the optical path conversion element PR. In position P1, ray height of ray height and the off-axis light flux LB _Offax the axial beam LB _ax is the lowest. Therefore, the position P1 is a predetermined position.

  As described above, the first opening ST1 and the second opening ST2 may be located closer to the object side than the predetermined position, or closer to the image side than the predetermined position. In FIG. 2, the first opening ST1 and the second opening ST2 are located closer to the object side than the position P1.

More specifically, the first opening ST1 and the second opening ST2 are located on the object side _{surface SPLf} of the parallel plate PL. By doing in this way, the stray light LB _flar reflected by the inner surface of the lens frame BAL can be shielded by the first opening ST1.

The stray light LB _flar reflected by the inner surface of the lens frame BAL gradually approaches the optical axis until reaching the position P1. Therefore, as the positions of the first opening ST1 and the second opening ST2 approach the position P1, the opening diameter of the first opening ST1 and the opening diameter of the second opening ST2 gradually decrease.

The object side surface S _PLf of the parallel plate PL is located _closest to the position P1, and is a place where the first opening ST1 and the second opening ST2 can be physically provided. Therefore, it is preferable that the first opening ST1 and the second opening ST2 are positioned on the object side _{surface SPLf} of the parallel plate PL.

By doing in this way, both the opening diameter of 1st opening part ST1 and the opening diameter of 2nd opening part ST2 can be made small. As the aperture diameter decreases, the area for blocking stray light LB _flar increases. As a result, more stray light LB _flar can be shielded.

  In the stereoscopic endoscope imaging apparatus of the present embodiment, it is preferable that the first opening and the second opening are located on the image side with respect to a predetermined position.

  In this way, it is possible to realize a stereoscopic endoscope imaging apparatus having an optical system with little stray light. In addition, an imaging apparatus for a stereoscopic endoscope that can be easily manufactured can be realized.

  In the stereoscopic endoscope imaging apparatus of the present embodiment, the first opening and the second opening are preferably located on the image side surface of the optical path conversion element.

FIG. 3 is a diagram illustrating another arrangement example of the openings. As shown in FIG. 3, the position P1 is the position of the joint surface between the parallel plate PL and the optical path conversion element PR. In position P1, ray height of ray height and the off-axis light flux LB _Offax the axial beam LB _ax is the lowest. Therefore, the position P1 is a predetermined position.

  As described above, the first opening ST1 and the second opening ST2 may be located closer to the object side than the predetermined position, or closer to the image side than the predetermined position. In FIG. 3, the first opening ST1 and the second opening ST2 are located on the image side with respect to the position P1.

More specifically, the first opening ST1 and the second opening ST2 are located on the image side surface S _PRr of the optical path conversion element PR. By doing in this way, the stray light LB _flar reflected by the inner surface of the lens frame BAL can be shielded by the first opening ST1.

On the image side from the position P1, the stray light LB _flar reflected by the inner surface of the lens frame BAL gradually moves away from the optical axis as the distance from the position P1 increases. Therefore, the opening diameter of the first opening ST1 and the opening diameter of the second opening ST2 gradually increase as the position of the first opening ST1 and the position of the second opening ST2 move away from the position P1. .

The image side surface S _PRr of the optical path conversion element PR is located _closest to the position P1, and is a place where the first opening ST1 and the second opening ST2 can be physically provided. Therefore, it is preferable that the first opening ST1 and the second opening ST2 are positioned on the image side surface S _PRr of the optical path conversion element PR.

By doing in this way, both the opening diameter of 1st opening part ST1 and the opening diameter of 2nd opening part ST2 can be made small. As the aperture diameter decreases, the area for blocking stray light LB _flar increases. As a result, more stray light LB _flar can be shielded.

  The stereoscopic endoscope imaging apparatus of the present embodiment further includes an opaque flat plate, the parallel flat plate is a colorless and transparent flat plate, and the first opening and the second opening are formed in an opaque flat plate. It is preferable that the hole is made.

  FIG. 4 is a diagram illustrating a specific example 1 of the opening. FIG. 4A shows the case where the opening is separated from the parallel plate, and FIG. 4B shows the case where the opening and the parallel plate are integrated.

  When the parallel plate PL is a colorless and transparent plate, the parallel plate PL itself cannot shield stray light. The optical path conversion element PR is also a colorless and transparent element. Therefore, stray light cannot be shielded by the optical path conversion element PR itself. Therefore, stray light can be shielded by using the light shielding member 1.

  In the stereoscopic endoscope imaging apparatus of the present embodiment, the light shielding member 1 is constituted by an opaque flat plate 2 as shown in FIG. The opaque flat plate 2 is provided with a first opening 3 and a second opening 4. The first opening 3 and the second opening 4 are through holes formed in the opaque flat plate 2.

  The 1st opening part 3 and the 2nd opening part 4 should just be located in the object side rather than a predetermined position. The predetermined position is the position of the joint surface between the parallel plate PL and the optical path conversion element PR. Therefore, as shown in FIG. 4A, the light shielding member 1 is disposed at a position away from the parallel plate PL.

  The optical system of the endoscope is small and the total length of the optical system is very short. Therefore, the thickness of the opaque flat plate 2 tends to be thin. When the thickness of the opaque flat plate 2 becomes too thin, it becomes difficult to hold the light shielding member 1 alone. Even if the light shielding member 1 can be held alone, it is difficult to accurately position the light shielding member 1 within the lens frame BAL.

  Therefore, it is preferable to integrate the opaque flat plate 2 with the parallel flat plate PL. By doing so, the light shielding member 1 can be easily held, and the light shielding member 1 can be accurately positioned. As a result, stray light can be blocked more accurately.

  Moreover, the 1st opening part 3 and the 2nd opening part 4 can be located in the object side surface of the parallel plate PL by integration. Therefore, both the opening diameter of the first opening 3 and the opening diameter of the second opening 4 can be reduced. As a result, more stray light can be shielded.

  The parallel plate PL is integrated with the optical path conversion element PR. Therefore, by integrating the light shielding member 1 with the parallel plate PL, as shown in FIG. 4B, the light shielding member 1, the parallel plate PL, and the optical path conversion element PR are integrated. As a result, an imaging apparatus for a stereoscopic endoscope that can be easily manufactured can be realized.

  FIG. 5 is a diagram showing a specific example 2 of the opening. FIG. 5A shows a case where the opening is separated from the optical path conversion element, and FIG. 5B shows a case where the opening and the optical path conversion element are integrated. The same components as those in FIG. 4A are denoted by the same reference numerals and description thereof is omitted.

  The 1st opening part 3 and the 2nd opening part 4 should just be located in the image side rather than a predetermined position. The predetermined position is the position of the joint surface between the parallel plate PL and the optical path conversion element PR. Therefore, as shown in FIG. 5A, the light shielding member 1 is disposed at a position away from the optical path conversion element PR.

  As described above, the thickness of the opaque flat plate 2 tends to be thin. When the thickness of the opaque flat plate 2 becomes too thin, it becomes difficult to hold the light shielding member 1 alone. Even if the light shielding member 1 can be held, it is difficult to accurately position the light shielding member 1 within the lens frame BAL.

  Therefore, it is preferable to integrate the opaque flat plate 2 with the optical path conversion element PR. By doing so, the light shielding member 1 can be easily held, and the light shielding member 1 can be accurately positioned. As a result, stray light can be blocked more accurately.

  Further, by integration, the first opening 3 and the second opening 4 can be positioned on the image side surface of the optical path conversion element PR. Therefore, both the opening diameter of the first opening 3 and the opening diameter of the second opening 4 can be reduced. As a result, more stray light can be shielded.

  The optical path conversion element PR is integrated with the parallel plate PL. Therefore, by integrating the light shielding member 1 with the optical path conversion element PR, as shown in FIG. 5B, the light shielding member 1, the parallel plate PL, and the optical path conversion element PR are integrated. As a result, an imaging apparatus for a stereoscopic endoscope that can be easily manufactured can be realized.

  In the stereoscopic endoscope imaging apparatus of the present embodiment, the parallel flat plate is a colorless and transparent flat plate, and on the object side surface of the parallel flat plate or the image side surface of the optical path conversion element, the light shielding portion, the first opening portion, 2 openings are formed, and the light shielding part is preferably formed of a light shielding material.

  FIG. 6 is a diagram illustrating a specific example 3 of the opening. FIG. 6A is a front view of the opening, and FIGS. 6B and 6C are views showing a place where the opening is formed.

  When the parallel plate PL is a colorless and transparent plate, the parallel plate PL itself cannot shield stray light. The optical path conversion element PR is also a colorless and transparent element. Therefore, stray light cannot be shielded by the optical path conversion element PR itself. Therefore, stray light can be shielded by forming the light shielding region 10 on the parallel plate PL or by forming the light shielding region 10 on the optical path conversion element PR.

  In the stereoscopic endoscope imaging apparatus of the present embodiment, as shown in FIG. 6A, the light shielding region 10 includes a light shielding portion 11, a first opening portion 12, a second opening portion 13, and the like. Is formed. The light shielding part 11 is made of a light shielding material. Examples of the method for forming the light shielding part 11 include coating and vapor deposition. The light shielding region 10 can provide the same effect as the light shielding member 1.

  The light shielding region 10 may be formed on the parallel plate PL or the optical path conversion element PR. In FIG. 6B, the light shielding region 10 is formed on the object side surface of the parallel plate PL. In FIG. 6C, the light shielding region 10 is formed on the image side surface of the optical path conversion element PR.

  In the stereoscopic endoscope imaging apparatus of the present embodiment, it is preferable that the parallel flat plate is formed of an opaque material, and the first opening and the second opening are holes formed in the parallel flat plate.

  When the parallel plate PL is a colorless and transparent plate, the parallel plate PL itself cannot shield stray light. The optical path conversion element PR is also a colorless and transparent element. Therefore, stray light cannot be shielded by the optical path conversion element PR itself. Therefore, stray light can be shielded by forming the parallel plate PL with an opaque material.

  FIG. 7 is a diagram showing a specific example 4 of the opening. FIG. 7A is a front view of the opening, and FIG. 7B is a cross-sectional view of the opening.

  In the stereoscopic endoscope imaging apparatus of the present embodiment, as shown in FIG. 7A, the light shielding member 20 is configured by a parallel plate PL. An opaque material is used for the parallel plate PL. The parallel plate PL is provided with a first opening 21 and a second opening 22.

  As shown in FIG. 7B, the first opening 21 and the second opening 22 are through holes formed in the parallel plate PL. The light shielding member 20 can provide the same effect as the light shielding member 1.

  In the light shielding member 20, the refractive index between the object side surface and the image side surface is 1. When the parallel plate PL is a colorless and transparent flat plate, the refractive index between the object side surface and the image side surface is greater than 1. Thus, the light path length differs between the light shielding member 20 and the colorless and transparent flat plate.

  The first optical system OBJ1 and the second optical system OBJ2 shown in FIG. 1 are optical systems on the premise that a parallel plate PL is a colorless and transparent plate. Therefore, the light shielding member 20 cannot be used in the first optical system OBJ1 and the second optical system OBJ2. A new optical system based on the use of the light shielding member 20 is required.

  The stereoscopic endoscope imaging apparatus according to the present embodiment includes a third opening located in the first optical path and a fourth opening located in the second optical path, and the third opening. The fourth opening is preferably located on the image side with respect to the predetermined position.

  As shown in FIG. 1, the places where the openings that block stray light are arranged exist on both sides of a predetermined position. As described above, stray light can be shielded by positioning the opening on one side of the predetermined position. However, the openings may be positioned on both sides of the predetermined position.

  Therefore, the third opening and the fourth opening are used. The third opening and the fourth opening are different from the first opening and the second opening. The first opening and the second opening are positioned closer to the object side than the predetermined position, and the third opening and the fourth opening are positioned closer to the image side than the predetermined position. By doing in this way, an opening part can be located in the both sides of a predetermined position.

  The third opening is located in the first optical path, and the fourth opening is located in the second optical path. A first opening and a third opening are located in the first optical path, and a second opening and a fourth opening are located in the second optical path.

  Thus, in the stereoscopic endoscope imaging apparatus of the present embodiment, the number of openings located on the optical path increases. Therefore, stray light that could not be blocked by the first opening or the second opening can be blocked by the third opening and the fourth opening. As a result, more stray light can be shielded.

  In the stereoscopic endoscope imaging apparatus of the present embodiment, it is preferable that the third opening and the fourth opening are located on the image side surface of the optical path conversion element.

  As shown in FIG. 4A and FIG. 5B, the places where the first opening and the second opening are arranged exist on both sides of the predetermined position. As described above, stray light can be blocked by positioning the first opening and the second opening on one side of the predetermined position. However, the openings may be positioned on both sides of the predetermined position.

  As described above, the stereoscopic endoscope imaging apparatus according to the present embodiment includes the third opening and the fourth opening. The third opening and the fourth opening are different from the first opening and the second opening. The first opening and the second opening are positioned on the object side surface of the parallel plate, and the third opening and the fourth opening are positioned on the image side surface of the optical path conversion element. By doing in this way, an opening part can be located in the both sides of a predetermined position.

  In addition, the first opening, the second opening, the third opening, and the fourth opening are located at a location closest to the predetermined position. Therefore, the opening diameter of the first opening, the opening diameter of the second opening, the opening diameter of the third opening, and the opening diameter of the fourth opening can be reduced. As the aperture diameter decreases, the area for blocking stray light increases. As a result, more stray light can be shielded.

  The stereoscopic endoscope imaging apparatus of the present embodiment further includes an opaque flat plate, the parallel flat plate is a colorless and transparent flat plate, and the third opening and the fourth opening are formed in an opaque flat plate. It is preferable that the hole is made.

  FIG. 8 is a diagram illustrating a specific example 5 of the opening. FIG. 8A shows the case where the opening is separated from the parallel plate and the optical path conversion element, and FIG. 8B shows the case where the opening, the parallel plate and the optical path conversion element are integrated. Yes. The same components as those in FIG. 4A are denoted by the same reference numerals and description thereof is omitted.

  As described above, more stray light can be blocked by positioning the openings on both sides of the predetermined position. Specifically, the first opening and the second opening are positioned closer to the object side than the predetermined position, and the third opening and the fourth opening are positioned closer to the image side than the predetermined position. .

  In the stereoscopic endoscope imaging apparatus of the present embodiment, as shown in FIG. 8A, the light shielding member 1 is located on the object side of the parallel plate PL, and the light shielding member 30 is located on the image side of the optical path conversion element PR. doing.

  The light shielding member 30 is configured by an opaque flat plate 31. The opaque flat plate 31 is provided with a third opening 32 and a fourth opening 33. The third opening 32 and the fourth opening 33 are through holes formed in the opaque flat plate 31.

  In the stereoscopic endoscope imaging apparatus of the present embodiment, the light shielding member 1 is located closer to the object side than the predetermined position, and the light shielding member 30 is located closer to the image side than the predetermined position. The number of openings to be increased. Therefore, the stray light that could not be blocked by the light blocking member 1 can be blocked by the light blocking member 30. As a result, more stray light can be shielded.

  As described above, the thickness of the opaque flat plate 2 tends to be thin. For this reason, the opaque flat plate 2 is preferably integrated with the parallel flat plate PL. Similarly, the thickness of the opaque flat plate 31 tends to be thin. For this reason, the opaque flat plate 31 is preferably integrated with the optical path conversion element PR.

  By doing in this way, the light shielding member 1 and the light shielding member 30 can be easily held, and the light shielding member 1 and the light shielding member 30 can be accurately positioned. As a result, stray light can be blocked more accurately.

  Further, by integration, the first opening 3 and the second opening 4 can be positioned on the object side surface of the parallel plate PL, and the third opening 32 and the fourth opening 33 are connected to the optical path. It can be positioned on the image side of the conversion element PR. Therefore, the opening diameter of the first opening, the opening diameter of the second opening, the opening diameter of the third opening, and the opening diameter of the fourth opening can be reduced. As the aperture diameter decreases, the area for blocking stray light increases. As a result, more stray light can be shielded.

  The optical path conversion element PR and the parallel plate PL are integrated. Therefore, by integrating the light shielding member 1 with the parallel plate PL and integrating the light shielding member 30 with the optical path conversion element PR, as shown in FIG. 8B, the light shielding member 1, the parallel plate PL, and the optical path conversion element PR. And the light shielding member 30 is integrated. As a result, an imaging apparatus for a stereoscopic endoscope that can be easily manufactured can be realized.

  In the stereoscopic endoscope imaging apparatus of the present embodiment, the light shielding part, the third opening part, and the fourth opening part are formed on the image side surface of the optical path conversion element, and the light shielding part is made of a light shielding material. Preferably it is formed.

  As shown in FIGS. 6A and 6C, a light shielding portion and an opening can be formed on the image side surface of the optical path conversion element using a light shielding material. In the light shielding region 10 shown in FIG. 6A, a light shielding portion 11, a first opening portion 12, and a second opening portion 13 are formed. If the first opening 12 is replaced with the third opening and the second opening 13 is replaced with the fourth opening, the light shielding portion, the third opening, 4 openings can be formed.

  In the stereoscopic endoscope imaging apparatus of the present embodiment, it is preferable that an aperture stop is disposed at a predetermined position.

  The aperture stop has two openings. The entrance pupil is an image of an aperture stop formed by a lens on the object side of the aperture stop. Therefore, the stereoscopic endoscope imaging apparatus of the present embodiment has two entrance pupils. If the positions of the two entrance pupils vary, stereoscopic vision becomes difficult.

  In the stereoscopic endoscope imaging apparatus of the present embodiment, an aperture stop is disposed at a predetermined position. The predetermined position is between the object side surface of the parallel plate and the image side surface of the optical path conversion element. The parallel plate and the optical path conversion element are integrated. Therefore, the brightness stop is positioned on the image side surface of the parallel plate.

  In the parallel plate, light refraction occurs between the object side surface and the image side surface. However, the angle of the light beam incident on the object side surface and the angle of the light beam emitted from the image side surface are the same. That is, unlike a lens or an optical path conversion element, a parallel plate does not have a refractive power that bends a light beam. Therefore, by arranging the aperture stop on the image side of the parallel plate, it is possible to significantly reduce the position variation of the entrance pupil as compared with the case where it is arranged on the image side of the optical path conversion element.

  In addition, since the parallel plate is formed of a single member, there is an effect that the variation of the parallel plate can be minimized as compared with the case where two parallel plates are used.

  In the stereoscopic endoscope imaging apparatus of the present embodiment, the aperture of the aperture stop is a hole formed in an opaque flat plate, and the aperture stop is located between the parallel plate and the optical path conversion element, The parallel plate, the aperture stop, and the optical path conversion element are preferably integrated.

  FIG. 9 is a diagram illustrating an arrangement example of the aperture stops. FIG. 9A shows the case where the opening is separated from the parallel plate and the optical path conversion element, and FIG. 9B shows the case where the opening, the parallel plate and the optical path conversion element are integrated. Yes. The same components as those in FIG. 4A are denoted by the same reference numerals and description thereof is omitted.

  In the stereoscopic endoscope imaging apparatus of the present embodiment, as shown in FIG. 9A, the light shielding member 1 is positioned on the object side of the parallel plate PL, and the brightness is between the parallel plate PL and the optical path conversion element PR. A diaphragm 40 is located.

  In FIG. 9A, the brightness stop 40 is located away from the parallel plate PL and the optical path conversion element PR for easy viewing. However, as will be described later, the parallel plate PL and the optical path conversion element PR are integrated. Therefore, actually, the aperture stop 40 is in close contact with the parallel plate PL and the optical path conversion element PR.

  The brightness stop 40 is composed of an opaque flat plate 41. The opaque flat plate 41 is provided with an opening 42 and an opening 43. The opening 42 and the opening 43 are through holes formed in the opaque flat plate 41.

  As described above, the optical system of the endoscope is small and the total length of the optical system is very short. Therefore, like the opaque flat plate 2, the thickness of the opaque flat plate 41 tends to be thin. If the opaque flat plate 41 is too thin, it is difficult to hold the aperture stop 40 alone. Even if the brightness stop 40 can be held alone, it is difficult to accurately position the brightness stop 40 in the lens frame BAL.

  In the stereoscopic endoscope imaging apparatus of the present embodiment, the brightness stop 40 is located between the parallel plate PL and the optical path conversion element PR. Moreover, the parallel plate PL and the optical path conversion element PR are integrated. Therefore, the aperture stop 40 is integrated with the parallel plate PL and the optical path conversion element PR so as to be sandwiched between the parallel plate PL and the optical path conversion element PR. As a result, the aperture stop 40 can be easily held and the aperture stop 40 can be accurately positioned.

  The stereoscopic endoscope imaging apparatus according to the present embodiment has two entrance pupils. If the positions of the two entrance pupils vary, stereoscopic vision becomes difficult. The variation in the positions of the two entrance pupils includes a variation in position in the optical axis direction and a variation in position in a plane orthogonal to the optical axis.

  If the position of the opening 42 and the position of the opening 43 are different in the optical axis direction, the positions of the two entrance pupils also vary in the optical axis direction. In this case, stereoscopic viewing becomes difficult.

  In the stereoscopic endoscope imaging apparatus of the present embodiment, the opening 42 and the opening 43 are formed on a single flat plate. Further, the aperture stop 40 is integrated with the parallel plate PL. Therefore, the position of the opening 42 and the position of the opening 43 can be made substantially the same in the optical axis direction.

  If it can do in this way, the position error of the brightness stop 40 can be minimized with respect to the optical system located closer to the object side than the brightness stop 40. As a result, variations in the positions of the two entrance pupils in the optical axis direction can be reduced.

  Further, the parallax necessary for stereoscopic viewing occurs in a direction orthogonal to the two optical axes. Therefore, an interval between two entrance pupils in a direction orthogonal to the two optical axes (hereinafter referred to as “parallax direction”) is also important. If this interval deviates from the design value, sufficient parallax cannot be obtained, or the parallax becomes too large and stereoscopic vision becomes difficult.

  In the stereoscopic endoscope imaging apparatus of the present embodiment, the opening 42 and the opening 43 are formed on a single flat plate. In this case, the opening 42 and the opening 43 can be formed so that the deviation from the design value is minimized as compared with the method of using two members having one opening on one flat plate. Therefore, it is possible to minimize the displacement of the position in the plane orthogonal to the optical axis. As a result, it is possible to reduce variations in the positions of the two entrance pupils in a plane orthogonal to the optical axis.

  Furthermore, there is no need to adjust the relative position between the opening 42 and the opening 43 during assembly. Therefore, errors during assembly can be reduced.

  Further, the aperture stop 40 is integrated with the parallel plate PL. As described above, since the parallel plate PL is composed of a single member, the shape and size of the outer diameter can be freely set. Furthermore, the outer diameter of the parallel plate PL can be made a shape suitable for positioning, and the outer periphery and the optical surface can be processed with high accuracy.

  Therefore, for the opening 42 and the opening 43, errors in the optical axis direction can be reduced. As a result, variations in the positions of the two entrance pupils in the optical axis direction can be reduced.

  As described above, the opaque flat plate 2 is preferably integrated with the parallel flat plate PL. By doing so, the light shielding member 1 can be easily held, and the light shielding member 1 can be accurately positioned. As a result, stray light can be blocked more accurately.

  The optical path conversion element PR, the aperture stop 40 and the parallel plate PL are integrated. Therefore, by integrating the light shielding member 1 with the parallel plate PL, as shown in FIG. 9B, the light shielding member 1, the parallel plate PL, the brightness stop 40, and the optical path conversion element PR are integrated. As a result, an imaging apparatus for a stereoscopic endoscope that can be easily manufactured can be realized.

  As shown in FIG. 7B, when the parallel plate PL is made of an opaque material, the aperture stop 40 may be arranged on the image side surface of the parallel plate PL. The opening diameter of the first opening 21 and the opening diameter of the second opening 22 are larger than the opening diameter of the opening of the brightness stop 40. Therefore, the through hole may be formed so that the diameter decreases from the object side surface toward the image side surface.

  In the stereoscopic endoscope imaging apparatus according to the present embodiment, the light shielding portion and the aperture of the aperture stop are formed on the image side surface of the parallel plate, and the light shielding portion on the image side surface of the parallel plate is formed of a light shielding material. It is preferable that

  As shown in FIGS. 6A and 6B, the light shielding portion and the opening can be formed on the object side surface of the parallel plate PL using the light shielding material. However, the surface on which the light shielding portion and the opening can be formed is not limited to this surface. As a matter of course, the light shielding part and the opening part can be formed on the image side surface of the parallel plate PL using the light shielding material.

  In the light shielding region 10 shown in FIG. 6A, a light shielding portion 11, a first opening portion 12, and a second opening portion 13 are formed. If the first opening 12 and the second opening 13 are replaced with the aperture of the aperture stop, the light blocking portion and the aperture of the aperture stop can be formed on the image side surface of the parallel plate PL.

  Further, in the stereoscopic endoscope imaging apparatus of the present embodiment, the light shielding portion and the aperture of the aperture stop are formed on the object side surface of the optical path conversion element, and the light shielding portion on the object side surface of the optical path conversion element is It is preferably formed of a light shielding material.

  As shown in FIGS. 6A and 6C, a light shielding portion and an opening can be formed on the image side surface of the optical path conversion element PR using a light shielding material. However, the surface on which the light shielding portion and the opening can be formed is not limited to this surface. As a matter of course, the light shielding portion and the opening can be formed on the object side surface of the optical path conversion element PR using the light shielding material.

  In the light shielding region 10 shown in FIG. 6A, a light shielding portion 11, a first opening portion 12, and a second opening portion 13 are formed. If the first opening 12 and the second opening 13 are replaced with the aperture of the aperture stop, the light blocking portion and the aperture of the aperture stop can be formed on the object side of the optical path conversion element PR. .

  In the stereoscopic endoscope imaging apparatus of the present embodiment, it is preferable that the optical path conversion element is constituted by a single member.

  FIG. 10 is a diagram illustrating an optical path conversion element. The same components as those in FIGS. 8B and 9B are denoted by the same reference numerals, and description thereof is omitted.

  In FIG. 8B and FIG. 9B, the optical path conversion element PR is composed of two members. On the other hand, in the stereoscopic endoscope imaging apparatus according to the present embodiment, as shown in FIG. 10, the optical path conversion element PR ′ is composed of a single member.

  Hereinafter, the case where the optical path conversion element is configured by a single member and the case where the optical path conversion element is configured by two members are compared. It is assumed that a right-angle prism is used as the optical path conversion element. In this case, the optical path conversion element has an entrance surface, a reflection surface, and an exit surface.

  Further, it is assumed that the first optical axis AX1f and the second optical axis AX2f are parallel. The first optical axis AX1f is the optical axis of the first optical path on the object side with respect to the optical path conversion element. The second optical axis AX2f is the optical axis of the second optical path closer to the object side than the optical path conversion element.

  When the optical path conversion element is composed of a single member, a single reflecting surface is located across the two optical paths. Therefore, both the first optical path and the second optical path are bent at the same reflecting surface.

  The angle of the reflecting surface with respect to the incident surface is the same at any position within the reflecting surface. In this case, the direction of the reflecting surface is the same at the position where it intersects with the first optical axis AX1f and at the position where it intersects with the second optical axis AX2f.

  As described above, the first optical axis AX1f and the second optical axis AX2f are parallel to each other. That is, the direction of the first optical axis AX1f and the direction of the second optical axis AX2f are the same. Therefore, the direction of the first optical axis AX1r and the direction of the second optical axis AX2r are also the same. The first optical axis AX1r is the optical axis of the first optical path on the image side with respect to the optical path conversion element. The second optical axis AX2r is the optical axis of the second optical path on the image side with respect to the optical path conversion element.

  Further, the distance between the incident surface and the reflecting surface is the same for the first optical path and the second optical path. Therefore, the first optical axis AX1r and the second optical axis AX2r are located in the same plane parallel to the incident surface. That is, there is no deviation in the direction orthogonal to the parallax direction between the position of the first optical axis AX1r and the position of the second optical axis AX2r.

  Thus, when the optical path conversion element is formed of a single member, there is no need to adjust the direction of the first optical axis AX1r or the direction of the second optical axis AX2r. Further, there is no need to adjust the relative distance or the relative position between the first optical axis AX1r and the second optical axis AX2r.

  When the optical path conversion element is composed of two members, a reflecting surface is located in each of the two optical paths. Therefore, the first optical path and the second optical path are bent at different reflecting surfaces, respectively.

  As described above, in a single member, the angle of the reflecting surface with respect to the incident surface is the same at any position in the reflecting surface. However, the angle of the reflecting surface with respect to the incident surface is not necessarily the same between one member and the other member. In this case, the direction of the reflecting surface is different between a position intersecting with the first optical axis AX1f and a position intersecting with the second optical axis AX2f.

  As described above, the first optical axis AX1f and the second optical axis AX2f are parallel to each other. That is, the direction of the first optical axis AX1f and the direction of the second optical axis AX2f are the same. However, since the direction of the reflecting surface is different between the two members, the direction of the first optical axis AX1r is different from the direction of the second optical axis AX2r.

  In addition, the distance between the incident surface and the reflecting surface is not necessarily the same between the one member and the other member. In this case, the distance between the incident surface and the reflecting surface is different between the first optical path and the second optical path. As a result, the first optical axis AX1r and the second optical axis AX2r are not positioned in the same plane parallel to the incident surface. That is, a shift in a direction orthogonal to the parallax direction occurs between the position of the first optical axis AX1r and the position of the second optical axis AX2r.

  Thus, when the optical path conversion element is composed of two members, it is necessary to adjust the direction of the first optical axis AX1r and the direction of the second optical axis AX2r. In addition, it is necessary to adjust the relative distance and the relative position between the first optical axis AX1r and the second optical axis AX2r.

  One member and the other member may require adjustment even when the angle of the reflecting surface with respect to the incident surface is the same and the distance between the incident surface and the reflecting surface is the same.

As shown in FIG. 1, the optical path conversion element, the height of light rays ray height and an off-axis light flux LB _Offax the axial beam LB _ax is low. Therefore, the two members can be reduced in size. When two miniaturized members are joined in parallel, the two optical axes must be brought close to each other.

  However, in order to ensure an appropriate parallax, the distance between the two optical axes needs to be increased to some extent. Therefore, the two members are integrated with the parallel plate in a separated state.

  In this case, one member can be rotated around the first optical axis AX1f. The other member is in a state of being rotatable around the second optical axis AX2f. Therefore, it is necessary to adjust the direction of the first optical axis AX1r and the direction of the second optical axis AX2r.

  As described above, when the optical path conversion element is composed of two members, the necessity for adjustment at the time of assembly is significantly higher than when the optical path conversion element is composed of a single member. .

  If the adjustment at the time of assembly is insufficient, the formation position of the optical image and the orientation of the optical image do not match the design position and orientation. Such inconsistencies can be corrected by image processing. However, in consideration of cost, such a mismatch is not preferable.

  In order to prevent such inconsistency from occurring, a great deal of time must be spent on adjustment during assembly. However, if it takes time for adjustment during assembly, work efficiency during assembly is greatly reduced.

  For this reason, it is preferable to configure the optical path conversion element with a single member. By configuring the optical path conversion element with a single member, it is possible to prevent a reduction in work efficiency during assembly. Further, correction by image processing is not necessary. Therefore, an increase in cost can be suppressed.

  In the stereoscopic endoscope imaging apparatus according to the present embodiment, the optical path conversion element includes a first optical path conversion element and a second optical path conversion element, and the first optical path conversion element and the second optical path conversion element are It is preferable that they are configured separately.

  As described above, when the optical path conversion element is composed of two members, the necessity for adjustment at the time of assembly is significantly higher than when the optical path conversion element is composed of a single member. .

However, when one member and the other member satisfy the following (I), (II), and (III), the optical path conversion element is configured by a single member by integrating the two members. It becomes equivalent to the case.
(I) The angle of the reflecting surface with respect to the incident surface is the same.
(II) The distance between the incident surface and the reflecting surface is the same.
(III) The two members have a size that can be joined in a parallel state.

  In this case, since the necessity for adjustment is reduced, the optical path conversion element can be composed of the first optical path conversion element and the second optical path conversion element.

  A specific example of an optical system used in the stereoscopic endoscope imaging apparatus of the present embodiment will be described. FIG. 11 is a cross-sectional view of an optical system used in the stereoscopic endoscope imaging apparatus of the present embodiment.

  The optical system for the stereoscopic endoscope includes, in order from the object side, a plano-concave negative lens L1, a positive meniscus lens L2 having a convex surface facing the image side, a negative meniscus lens L3 having a convex surface facing the image side, and a parallel plate PL, optical path conversion element PR, planoconvex positive lens L4, negative meniscus lens L5 having a convex surface facing the object side, and biconvex positive lens L6.

  The positive meniscus lens L2 and the negative meniscus lens L3 are cemented. The parallel plate PL and the optical path conversion element PR are joined. The negative meniscus lens L5 and the biconvex positive lens L6 are cemented.

  A cover glass C1 and a cover glass C2 are arranged on the image side of the biconvex positive lens L6. The cover glass C2 is a cover glass of the image sensor. The imaging surface I of the imaging device is located on the image side surface of the cover glass C2. Therefore, the optical image I is formed on the image side surface of the cover glass C2.

  The optical path of the optical system is bent at the reflection surface of the optical path conversion element PR. In this example, a right-angle prism is used as the optical path conversion element PR. The optical path after bending is orthogonal to the optical path before bending.

  Below, the numerical data of the said Example are shown. In the surface data, r is a radius of curvature of each lens surface, d is an interval between the lens surfaces, nd is a refractive index of d-line of each lens, and νd is an Abbe number of each lens.

  In various data, f is the focal length of the entire system, Fr is the radius of the flare stop, and Ar is the radius of the brightness stop.

Numerical example unit mm

Surface data surface number rd nd νd
1 ∞ 0.34 1.88815 40.76
2 0.51 0.27 1
3 (Aperture) ∞ 0.13 1
4 -2.484 0.45 1.62409 36.26
5 -0.639 0.3 1.75453 35.33
6 -0.84 0.317 1
7 (Aperture) ∞ 0.03 1
8 ∞ 0.3 1.93429 18.9
9 ∞ 0.0 1
10 (Aperture) ∞ 0.03 1
11 ∞ 0.70 1.93429 18.9
12 ∞ 0.03 1
13 (Aperture) ∞ 0.2388 1
14 ∞ 0.5 1.48915 70.23
15 -1.566 0.1777 1
16 6.745 0.3 1.74706 27.79
17 1.072 0.8 1.48915 70.23
18 -1.686 1.2991 1
19 ∞ 0.7 1.51825 64.14
20 ∞ 0.02 1.5119 64.06
21 ∞ 0.7 1.6 135 50.5
22 (imaging surface) ∞

Various data f 0.87
Fr (r3) 0.38
Fr (r7) 0.22
Fr (r13) 0.3
Ar (r10) 0.159

(Appendix)
In addition, the invention of the following structures is guide | induced from the above-mentioned embodiment.

(Additional item 1)
It further has an opaque flat plate,
The parallel plate is a colorless and transparent plate,
The imaging device for a stereoscopic endoscope, wherein the first opening and the second opening are holes formed in an opaque flat plate.
(Appendix 2)
The parallel plate is a colorless and transparent plate,
A light shielding portion, a first opening, and a second opening are formed on the object side surface of the parallel plate or the image side surface of the optical path conversion element,
The imaging device for a stereoscopic endoscope, wherein the light shielding part is formed of a light shielding material.
(Additional Item 3)
The parallel plate is made of an opaque material,
The imaging device for a stereoscopic endoscope, wherein the first opening and the second opening are holes formed in a parallel plate.
(Appendix 4)
A third opening located in the first optical path;
A fourth opening located in the second optical path,
The 3rd opening part and the 4th opening part are located in the image side rather than a predetermined position, The imaging device for stereoscopic endoscopes characterized by the above-mentioned.
(Appendix 5)
The imaging device for a stereoscopic endoscope, wherein the third opening and the fourth opening are located on an image side surface of the optical path conversion element.
(Appendix 6)
It further has an opaque flat plate,
The parallel plate is a colorless and transparent plate,
The imaging device for a stereoscopic endoscope, wherein the third opening and the fourth opening are holes formed in an opaque flat plate.
(Appendix 7)
A light blocking portion, a third opening, and a fourth opening are formed on the image side surface of the optical path conversion element,
The imaging device for a stereoscopic endoscope, wherein the light shielding part is formed of a light shielding material.
(Appendix 8)
The aperture of the aperture stop is a hole formed in an opaque flat plate,
The aperture stop is located between the parallel plate and the optical path conversion element,
A parallel endoscope, an aperture stop, and an optical path conversion element are integrated, and a stereoscopic endoscope imaging device.
(Appendix 9)
On the image side surface of the parallel plate, a light shielding portion and an aperture stop aperture are formed,
A stereoscopic imaging device, wherein a light shielding portion on an image side surface of a parallel plate is formed of a light shielding material.
(Appendix 10)
On the object side surface of the optical path conversion element, a light blocking portion and an aperture stop aperture are formed,
A stereoscopic imaging device, wherein the light shielding portion on the object side surface of the optical path conversion element is formed of a light shielding material.
(Appendix 11)
An optical imaging device for a stereoscopic endoscope, wherein the optical path conversion element is formed of a single member.
(Appendix 12)
The optical path conversion element includes a first optical path conversion element and a second optical path conversion element,
The imaging apparatus for stereoscopic endoscopes, wherein the first optical path conversion element and the second optical path conversion element are configured separately.

  Although various embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and may be implemented by appropriately combining the configurations of these embodiments without departing from the spirit of the present invention. The form is also within the scope of the present invention.

  As described above, the present invention is suitable for a stereoscopic endoscope imaging apparatus having an optical system with little stray light in a stereoscopic endoscope in which an optical system is configured by only two optical paths. The present invention is also suitable for a stereoscopic endoscope imaging device that is easy to manufacture.

OBJ1 first optical system OBJ2 second optical system OP1 first optical path OP2 second optical path L1 to L6 lens PL parallel plate PR optical path conversion element C1, C2 cover glass IS imaging element I optical image (imaging surface)
I1 1st optical image I2 2nd optical image BAL Mirror frame _Pin1 and _Pin2 The point on the inner surface of the mirror frame BAL
P1 position (predetermined position)
LB _flar stray light LB _{ax on-} axis light beam LB _offax off-axis light beam S brightness stop ST1 first aperture portion ST2 second aperture portion S _PLf parallel plate PL object side surface S _PRr optical path conversion element PR image side surface 1, 20, 30 Light-shielding member 2, 31 Opaque flat plate 3, 21 First opening 4, 22 Second opening 10 Light-shielding region 11 Light-shielding part 12 First opening 13 Second opening 32 Third opening 33 4th aperture 40 Brightness stop 41 Opaque flat plate 42, 43 Aperture AX1f 1st optical axis AX2f 2nd optical axis AX1r 1st optical axis AX2r 2nd optical axis

Claims (6)

A first optical system disposed in the first optical path and generating a first optical image;
A second optical system disposed in the second optical path and generating a second optical image;
An image sensor that captures the first optical image and the second optical image;
A parallel plate and an optical path conversion element are located in each of the first optical path and the second optical path,
The parallel plate and the optical path conversion element are integrated,
The parallel plate is composed of a single member,
The predetermined position is an arbitrary position between the object side surface of the parallel plate and the image side surface of the optical path conversion element,
In the first optical system and the second optical system, the light beam height of the on-axis light beam and the light beam height of the off-axis light beam are the lowest at the predetermined position.
The first opening is located in the first optical path;
The second opening is located in the second optical path,
Both the first opening and the second opening are located closer to the object side than the predetermined position, or closer to the image side than the predetermined position. Mirror imaging device.   The stereoscopic endoscope imaging apparatus according to claim 1, wherein the first opening and the second opening are located closer to the object side than the predetermined position.   The imaging apparatus for a stereoscopic endoscope according to claim 2, wherein the first opening and the second opening are located on an object side surface of the parallel plate.   The stereoscopic endoscope imaging apparatus according to claim 1, wherein the first opening and the second opening are located on an image side with respect to the predetermined position.   The stereoscopic endoscope imaging apparatus according to claim 4, wherein the first opening and the second opening are located on an image side surface of the optical path conversion element.   The imaging device for a stereoscopic endoscope according to any one of claims 1 to 5, wherein an aperture stop is disposed at the predetermined position.

Images